1. Field of the Invention
The present invention pertains to compositions comprising multiple quaternary ammonium salts (multiple quats), methods of using said compositions, and processes for making said compositions.
2. Description of Related Art
Organic quaternary ammonium salts, also known as tetraorgano ammonium salts, are compounds comprising positively-charged nitrogen atoms. These compounds comprise aliphatic chains, yet nevertheless can be water soluble in some instances.
The positive charge associated with a quaternary ammonium salt (“quat salt” or “multiple quat”) is unaffected by changes in pH. That is, the charge on the nitrogen center is not the result of simple protonation of an amine, so the pH of aqueous solutions of these salts may be adjusted over a wide range without causing the loss of the positive charge on the nitrogen center.
Quat salts that contain a group capable of forming a covalent bond with another molecule or with a polymer are sometimes called “cationizing” agents. Such cationizing agents have been used to impart permanent positive charge to polymers. Specifically, cationizing agents containing 2,3-epoxypropyl groups,
or 3-chloro-2-hydroxypropyl groups,
are particularly useful in such applications. In principle, these groups are capable of forming a covalent chemical bond by reaction with many organic functional groups—hydroxyl, thiols, primary and secondary amines, ketones, carboxylic acids, isocynates, substituted ureas, etc.
The present invention concerns cationizing agents containing either a 2,3-epoxypropyl group or a 3-chloro-2-hydroxypropyl group. These cationizing agents also contain two or more positive charges per molecule. Furthermore, these cationizing agents are capable of imparting permanent (as opposed to transient) positive charge to polymers by forming a covalent chemical bond with an appropriate substituent on the polymer.
The resulting “cationized” polymers have found use as flocculants in waste water treatment, as aids in the manufacture of paper, textiles, cements, and detergents, and as components of extrudable composites with epoxy-containing resins (as in U.S. Pat. No. 6,376,583 to Dow Chemical Company).
In certain instances, quaternary ammonium salts having a reactive functionality have been used to create cationic starch derivatives useful as flocculants in wastewater treatment, and in the manufacture of paper, textiles, cements, and detergents.
In some instances, such as in the manufacture of paper from recycled pulp, the cationic charge that can be imparted to starch with known cationizing agents is insufficient to overcome the effect of the high ionic strength processing medium. Furthermore, when sufficient charge can be achieved with known cationizing agents, it sometimes must be done so in a manner that renders that starch particle unacceptable for other reasons (e.g., excessive swelling). Other types of hydroxyl-containing polymers, such as the synthetic polyvinylalcohols, undergo that same cationizing reactions and suffer the same deficiencies in currently known cationizing agents.
U.S. Pat. Nos. 5,616,800 and 6,177,577 disclose dicationic and polycationic monoprimary alcohols. However the disclosed structures are linear and contain a single primary alcohol group at the terminus of the molecule, which may be less desirable features in certain applications.
For the aforementioned reasons, it would be desirable to discover quaternary ammonium salts comprising multiple positively-charged amine groups that have advantageous properties. It would also be useful to discover compounds and methods for making improved cationic carbohydrates for use in a variety of industries.